Conventionally, an optical fiber connector has a structure in which two optical fibers placed end to end are anchored within the same housing.
There are alignment positioning structures for optical fiber connectors having such structures as (1) a structure wherein optical fibers are inserted end to end in both ends of a fine narrow tube (called a "microcapillary" below), (2) a structure wherein optical fibers are placed together end to end in a positioning groove, and (3) a structure which supports the optical fibers and positions them in the center of three fine rods or three minute bowls. This optical fiber connector aligns a pair of optical fibers, places them end to end, and fastens or mechanically pins them into the alignment mechanism.
However, the following problems arise in the above optical fiber connector when the optical fiber is simply anchored in a housing.
First, because of differences in coefficient of thermal expansion between the housing in which the optical fibers are anchored end to end and the optical fibers, the end-to-end positioning of the optical fibers changes when there is a change in temperature. Thus, connection loss in the optical fibers becomes a problem.
Also, in the above housing the optical fibers are held by an elastic body which deteriorates over time, degrading its ability to hold the optical fibers. The end to end state of the fibers changes, and the connection loss fluctuates.
Furthermore, when a means that can suppress fluctuation in the connection loss is installed, the structure becomes complicated, and there is concern that much labor is necessary in the connecting of the optical fibers using this alignment positioning structure. Specifically, when such problems as breakage of a fiber in a fiber optical system or damage to an optical component occur, it is necessary that the connection work be speedily finished, and thus the development of an optical fiber connector which can connect optical fibers simply and accurately is desired.
In response to this need, the Applicants have already proposed an optical connector, such as that disclosed in PCT/JP96/02357 (International Application Number).
When assembled, this optical fiber connector generally has a structure comprising a component with a two piece structure having the form of a rod, and a C-shaped spring formed in a tube having a C-shape in cross-section applying a clamping force to the components inserted therein. In the center of the components, there is an alignment mechanism which can position the adjustment of optical fibers connected end to end and longitudinally inserted in both ends of this component. This alignment mechanism has such structures as (1) a structure into which optical fibers are inserted and placed end to end in both ends of a microcapillary, (2) a structure into which optical fibers are placed together end to end in a positioning groove, and (3) a structure into which optical fibers are positioned in the center of three fine rods or three minute bowls. By securely clamping the optical fiber inserted in the component by the clamping force of the C-shaped spring, the optical fiber connector securely supports the connected state of the optical fibers connected end to end, and at the same time makes possible the extraction and switching of optical fibers by inserting a wedge through the open part of the C-shaped spring and releasing the clamping force applied to the optical fiber.
However, because the above-described optical connector is small, the operation of stretching open the C-shaped spring is difficult, and when inserting the optical fiber, the optical fiber must be inserted into the component while it is being stretched open. Thus, in order to optically connect the optical fibers together at the desired connection loss, much labor is required, and there is insufficient operability. In addition, if the wedge is inserted with too much force or if a pinching force is applied for an excessively long period of time, small deformations of the components are produced, the insertion capacity of the C-shaped spring becomes unsplatform, and this will possibly influence the precision of the connection between the optical fibers in the optical fiber connector. Thus, it is necessary to pay careful attention to the operation. Because of this, the development of a special device allowing the convenient end to end connecting of optical fibers in an optical fiber connector while not exerting an excessive lateral pressure on the component is desirable.
In the optical connection of optical fibers together, there are many instances when connection switching is necessary. For example, leaving one fiber in place and replacing the other fiber is frequently desired. Thus, as a device for the above optical fiber connector, it is desirable that connection switching be easily performed.
In consideration of the above, the object of the present invention is to provide an optical fiber connection device and optical fiber connection method that makes possible easy end-to-end connection of optical fibers using an optical fiber connector of a type wherein a pair of optical fibers is inserted and connected end to end between components of a two piece structure.
In addition, it is a further object of the present invention to provide an optical fiber connection device and optical fiber connection method that facilitates easy connection switching of optical fibers.